Got my 34WK95U today, connect with the Displayport cable came with the monitor.
(FYI. It won't boot with Displayport 1.4, had to switch to 1.2 and update firmware for 1080Ti under WIndows to fix that.)
I can see 5120x2160 option but can only get 30Hz with that. Lower resolutions can go up to 60Hz, but not 2560x1080...
Everything works perfectly under windows, so I think it is macOS to blamed.
Anyone has a solution for this please mention me in your post, much appreciated.
BTW. I'm still on HS.
This Apple & Nvidia sh&*(^!t is making me miserable. ;(